Functional density of integrated circuit (IC) has never ceased to increase so as to accommodate even more components per chip area. The size of the components has to decrease along the course of the evolution. The scaling down is accompanied by inevitable complexity in design and fabrication.
With the advent of wafer level packaging of a micro electrical mechanical system (MEMS) device, these advances can be realized. MEMS devices provide a new perspective of what integrated circuits can achieve including power generation, light projection, force sensing, switching and combination of novel materials and process. Since MEMS devices incorporate multiple substrates, the scaffolding of the MEMS devices is relatively articulate. In the presence of movable members, protection mechanisms are employed to attenuate the impact caused by collision. While existing techniques for stiction prevention have been adequate, they have not been entirely satisfactory in all regards.